title: Comparison of PET-CT images with the histopathological picture of a resectable primary tumor for delineating GTV in nonsmall cell lung cancer.
abstract: OBJECTIVE
  This study was designed to investigate the feasibility of a method derived from fused positron emission tomography-computed tomography (PET-CT) images for the delineation of gross tumor volume (GTV) in nonsmall cell lung cancer (NSCLC) and to explore the correlation between PET-CT and histopathological findings.
  
  
  METHODS
  Thirty-seven patients were enrolled in this study; all patients were evaluated by PET-CT and underwent surgery within 1 week after the scan. The radiation oncologist, together with the radiologist, first delineated the GTV-based CT and then with an experienced nuclear medicine physician contoured the same GTV using the distinctive visual 'halo' in fused PET-CT images. The characteristics of the halo phenomenon were analyzed, including the standardized uptake value (SUV). The excised surgical specimens were labeled and the maximum diameter of the tumor in the right-left axis of the tissue blocks was measured on consecutive histopathology slides; the histopathological slice images were scanned using a digital pathology scanner after staining with hematoxylin and eosin.
  
  
  RESULTS
  The mean SUV of the external margins of the halos was 2.41±0.73 (range 1.4-4.1); the histopathological type and T-stage significantly influenced the SUV of the external margin of the halos (P=0.004 and 0.027). The correlation coefficients of maximum diameter in the right-left axis and in the anterior-posterior axis between fused PET-CT images and histopathology were 0.935 and 0.943, respectively; the values between CT imaging and histopathological examination were 0.82 and 0.763.
  
  
  CONCLUSIONS
  There is a correlation between GTV based on the'halo' of fused PET-CT images and the excised surgical specimen of primary tumor.It may be feasible to use the 'halo' characteristics in fused PET-CT images to delineate GTV in NSCLCs, but its reliability should be further investigated to establish an accurate spatial imaging-pathology correlation for primary tumors delineation in NSCLCs.
authors.affiliation: Department of Oncology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Lin
authors.forename: Bo
authors.initials: B
authors.lastname: Han
authors.forename: Lijuan
authors.initials: L
authors.lastname: Yu
authors.forename: Dan
authors.initials: D
authors.lastname: Shan
authors.forename: Ruizhi
authors.initials: R
authors.lastname: Wang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Ning
mesh_terms: D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000473:pathology* / Q000601:surgery; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden